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Can the sun save lives?

An innovative Swedish invention uses solar energy to heat and treat water in developing countries

Can the sun save lives?

Text by Mandi Keighran / Portrait: Christopher Hunt

What’s the big idea?
Solvatten is a small-scale solution for a big problem – a 10-litre container that makes unsafe water drinkable using solar energy. It also heats water to use for personal hygiene and rinsing food, and pre-heats water before cooking.

How does it work?
Everyone knows you can boil water to make it safe to drink, but it’s not such common knowledge that UV light also kills microorganisms. Solvatten – which is Swedish for “sun” and “water” – uses heat, UV and a built-in filter to clean contaminated water. To use it, you simply fill the Solvatten with water, unfold in a sunny place and wait two to six hours – an indicator shows when the treatment process is complete. “We haven’t seen anything else that combines the heating and treatment of water in this way,” says Solvatten’s founder, Swedish artist and inventor Petra Wadström. “It is unique.”

How does it work so quickly?
The patented design maximises the speed at which the water temperature rises (up to 75oC) and the amount of UV radiation to which the water is exposed. This is combined with a filter to reduce the cloudiness of the water. In very sunny places, like Somalia, Solvatten can be used up to four times each day, providing 40 litres of safe, warm water.

How important is this?

Very. Solvatten can offer safe drinking water to huge numbers of people in locations where there is polluted water and energy sources are scarce, yet there is plentiful sun. It treats water containing bacteria, viruses and parasites, producing water that meets the World Health Organisation’s guidelines for safe water. Solvatten also reduces the amount of firewood and charcoal used as household fuel. According to independent studies, one Solvatten will save up to six mid-sized trees for each year of use, thus reducing carbon emissions by up to two tonnes per year for each device.

Where did the idea come from?
“I developed Solvatten after seeing problems caused by the lack of safe drinking water in Indonesia,” says Wadström. “It took many years and prototypes but eventually the idea was realised. My mission is to provide Solvatten to everyone who has the need for safe water.”

How many people are using it?
“There are about 20,000 Solvattens out there today,” says Wadström. “Each one serves approximately five or six people in a family, so there are around 100,000 people using it.” That number looks set to grow rapidly.

How much does the Solvatten cost?
“I strongly believe in self-help,” Wadström says. “It is important we make Solvatten affordable and the users invest in it, so they value Solvatten and take good care of it.” So, in East Africa, the Solvatten currently sells for a subsidised price of US$20-30 (up to NOK180), and will last for seven years or more if treated with care. As volume increases, the price will come down further. There are also collaborations with various environmental organisations through which customers can offset their carbon footprint with Solvatten, making it more affordable to the end-user.

What else is Wadström involved in?

She recently set up the Solvatten Charitable Foundation to help provide Solvatten to those who need it most. A collaboration with the Norwegian Refugee Council will see Solvatten distributed in and around the Kakuma refugee camp in north Kenya to 100,000 people, many of them from South Sudan.

What does the future hold?

“We hope to find a strong partner who is already distributing other solar devices and has more global distribution,” says Wadström. “We currently work with large organisations like UN-Habitat and UNICEF, but we also want to work with smaller, local organisations. It is very important to be on the ground, getting to know people and finding acceptance.” 


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